The New York Times has a story about the problems of expanding CALEA to on peer-to-peer communications. The story discusses a Center for Democracy and Technology report on the topic by several experts. One signatory is Susan Landau, who writes in:
Our first concern is something that I have written about on multiple occasions, namely that an architected security breach---which is what a wiretap is---is exploitable not only by law enforcement but also by criminals, other nation states, etc. Then, to satisfy law enforcement, companies must either enable a 24/7 capability for wiretapping whenever law enforcement requires it or --- very dangerous --- give any law-enforcement organization, no matter how small and poorly secured, the ability to conduct the tap on its own. This is really dangerous. Finally, as Steve Bellovin, Matt Blaze, Sandy Clark, and I have written about elsewhere, ultimately this effort will be ineffective, and other tools will be needed. It will simply be too easy for sophisticated criminals to develop their own communications tools that omit the wiretapping capabilities the FBI is demanding. The result will be a weakened communications system that simultaneously doesn't provide what law enforcement claims it needs.